Nowadays, two different processes are used in web offset printing: heatset and coldset.
The coldset process is mostly used to print newspapers and paperbacks, with the printing ink drying purely by absorption.
In the heatset process, the paper is passed through a large dryer and a chill roll unit after the last printing unit. The length of the printing press is almost doubled by these two units. To ensure that the ink dries optimally, special heat-drying inks are used here.
The paper running through the printing machine at high speed is heated up in the dryer as the mineral oils contained in the printing ink only evaporate at around 200 degrees. The dry air that is blown onto the paper therefore has a temperature of around 250 degrees Celsius and heats not only the printing ink but also the paper to 100° to 120° Celsius. This process removes a great deal of moisture from the paper, as the water contained in the paper simply evaporates. As a result, difficulties such as the paper curling, bubbles or even static charging of the paper web arise. In addition, the resins in the printing ink become liquid, i.e. the ink becomes soft and sticky. Only when the ink is cooled in a flash at the end of the dryer by specially coated chill rolls does it become solid and acquire its characteristic heatset gloss.
The paper, which is very much affected by the heat, is moistened with a water-silicone mixture after the sudden cooling to 20° to 30° Celsius. The water moistens the paper, the silicone ensures that the print is scratch-resistant.
Papers used in heatset must therefore be highly resistant to heat, liquid loss, bubbles and swelling.
Due to the high energy consumption and stricter environmental regulations, heatset plants today are mainly operated with heat recovery systems.
Typical heatset colour profiles for printing and proofing are:
- PSO SNP Paper (ECI)
- ISONewspaper 26v4
Both are available on shop.proof.de as proof profiles.
A good video showing a heatset system can be found on youtube:
Heatset Video
You can also learn more about web offset on Wikipedia.
More articles related to this topic:
Proof.de: New video online
In this short image video we – the Proof GmbH – introduce us and our work. Find out who we are and what drives us. What do you think of our short film?
Fogra60 proofs for metal decor printing available
New PANTONE Formula Guides with incorrect ink formulations
Several errors have crept into the new PANTONE 2023 fan decks. In both the PANTONE Solid Coated and the Solid Uncoated color fans, there are colours for which the new ink formulations are incorrect. In the PANTONE Formula Guide Solid Coated fan 2023, PANTONE 107 C and PANTONE 108 C have absolutely identical ink recipes, as well as PANTONE 113 C and PANTONE 114 C. As the colors differ, this cannot be the correct. Several errors in the PANTONE Solid Uncoated fan 2023 In the PANTONE Solid Uncoated fan 2023 … read more
Proofs with Digimarc EAN codes and verification
Digimarc is a digital watermark that can be used to embed information in images, videos or other media. Digimarc watermarks are invisible to the human eye, but remain recognisable to special software or devices. Digimarc is becoming increasingly popular in the packaging sector in particular, as this technology allows the digits of the EAN barcode and more to be applied invisibly to all areas of the packaging. Digimarc and EAN barcode at the supermarket checkout When scanning at the checkout, the checkout staff do not have to search for the … read more
New iPhone colour measuring devices: xade nano+ in test
A new generation of colour measuring devices is entering the market: in contrast to the classic measuring devices, which are available as a fully encapsulated system either as a colourimeter or as a spectrophotometer, and then supply the data to a computer via an interface or app or display it directly, the new generation of colour measuring devices consist only of lighting and software, with the optics of a modern iPhone from Apple being used as the sensor. Until now, there have been two categories of measuring devices on the … read more
Proof GmbH 2021 Certified Again by Fogra with Fogra “Spot cert”
In 2021 proof.de was again Fogra certified including Fogra “Spot cert” certification, i.e. for the display of spot colours such as PANTONE C and U.
“Digital First” often means “Colour Problems Second!”
Whether it’s a large global corporation or a small company, the following often applies to designs or redesigns today: we develop everything for digital first.
MYIRO-9: New Spectrophotometer from KonicaMinolta in action
Over the last few months, we at Proof.de have been thinking about further improving our already very good colour measurement technology in terms of speed and measurement precision. Relatively quickly it became clear that only two devices would come into question: The KonicaMinolta MYIRO-9, the successor of the former FD-9, or the X-Rite ISIS 2 XL. The starting point: Since we at Proof GmbH have 5 proofing devices, the calibration of targets for profile optimisation is a time-critical undertaking for us. Therefore, we had been looking around for an upgrade of … read more
Proof.de is featured twice in the “Fogra Aktuell” magazine
In the current issue of Fogra News “Fogra Aktuell” Proof GmbH is involved in two places. Firstly, a summary of the Fogra report on our first FOGRA55 certification for seven-colour printing with extended colour space in CMYKOGV appeared. You can also find more information on our FOGRA55 certification on the Fogra website: https://fogra.org/en/press-releases/fogracert-erste-cpc-zertifizierung-fuer-fogra55-cmykogv-330 and on proofing.de: And secondly, there was a report on the completion of the research project for textile digital printing, FOGRA58, in which we were allowed to investigate and test the proof capability of the new textile … read more
Proof GmbH 2025 once again Fogra and Fogra “Spot Cert” certified
This year we once again created proofs for Fogra certification and sent them to Munich-Aschheim for testing. With these proof prints, which we print according to three different proof standards and on three different papers, we point out that we not only deliver excellent proof quality through internal quality controls and checks, but that the quality of our proofs is also measured and confirmed by external experts. We have now had test prints certified by Fogra for the 12th time. We have also been “Spot-cert” certified for the display of … read more